1. Field of the Invention
The present invention generally relates to a terminal registration method using a session initiation protocol, and more particularly to a terminal registration method using a session initiation protocol for increasing system efficiency and minimizing user mistakes by enabling a terminal to perform registration after receiving an IP (Internet Protocol) address and a telephone number from an Internet access device with the use of an MAC (Media Access Control) address.
2. Description of the Related Art
VoIP (Voice over Internet Protocol) is a communication technology providing a voice telephone service, multimedia conference, and others with the use of Internet protocol, creating various equipments and application services by interworking with IP networks and PSTN (Public Switched Telephone Network).
As for protocols mainly used for Internet phone implementation, there are H.323 suggested by ITU-T (International Telecommunication Union-Telecommunication), SIP (Session Initiation Protocol) of IETF (Internet Engineering Task Force), and MGCP (Media Gateway Control Protocol).
Currently, most equipment and service providers are supporting H.323 protocol of the ITU-T, but it is expected that the SIP of the IETF will be popular due to its various functions and expandability.
Generally, the SIP is an application layer control protocol for establishing, modifying, and terminating calls or multimedia sessions for multimedia communication such as videos and voices, and standards of the SIP are defined in an IETF RFC (request for comments) 2543 document.
The SIP is a portion of the entire framework suggested by an IETF MMUSIC (Multiparty Multimedia Session Control) working group to implement a multimedia multilateral communication system with SDP (Session Description Protocol: IETF RFC2327), SAP (Session Announcement Protocol: IETF RFC2974), RTSP (Real-Time Stream Protocol: IETF RFC2326), and SCCP (Simple Conference Control Protocol).
The SIP is an upper protocol of a UDP/TCP/IP (User Datagram Protocol/Transmission Control Protocol/Internet Protocol) layer, supporting both unicast and multicast sessions to start the sessions by inviting client/server protocols which transmitting/receiving SIP request and SIP response messages in request/response methods, to a multimedia conference.
The SIP request messages in RFC2543 provides 6 basic functions such as INVITE (Invitation for Session Participation), ACK (Confirm for INVITE Request), BYE (Call Terminate), REGISTER (UserAgent is registered in a Database of Redirect Server), CANCEL (Cancel a pending request), and OPTIONS (Queries the capabilities of the server). Moreover, SIP response messages are provided as 1xx (Information Response), 2xx (Successful Response), 3xx (Redirection Response), 4xx (Client Error, Request Failure), 5xx (Server Failure), and 6xx (Global Failure) for status codes.
A VoIP system based on SIP includes an SIP user agent composed of a UAC (User Agent Client) and a UAS (User Agent Server) and an SIP server composed of SIP proxy servers, a redirect server, a location server, and SIP gateways (SIP/H.323 gateway, SIP/PSTN gateway). In the location server, a server application receiving a REGISTER message is called a registration server or a registrar.
When receiving an SIP REGISTER request, an SIP registration server provides access information to other SIP servers.
When registering in a VoIP network to receive a call with a current IP address and a URL (Uniform Resource Locator), the user agent uses a REGISTER method. An SIP registration method is similar to that of a wireless communication terminal, thus a registration process is unnecessary when the user agent makes a call with the proxy server.
However, the registration process is necessary when the user agent receives a call from the proxy server managing a self domain, even though the user agent does not receive a location information service by IP address and SIP URL.
The above registration process is performed as follows: when the UAC is authenticated by transmitting a REGISTER request message to the proxy server from the UAC, the proxy server retransmits the REGISTER request message to a database of the location server and registers in the location server; the location server transmits a 200 OK response message to the proxy server; and when the proxy server retransmits the 200 OK response message to the UAC, the registration process is terminated.
The authentication process during the registration above will be described in detail as follows: the authentication process begins when the UAC transmits a 201 REGISTER message to the proxy server; at this time, among username, realm, and nonce transmitted when the 201 REGISTER message is initially sent, an incorrect nonce value is transmitted on purpose; the proxy server transmits a 401 Error message accordingly; then, the UAC retransmits the 201 REGISTER message, on this occasion, it sends correct values of the username, realm, and nonce; and the proxy server requests registration of the location server when the correct values are received, and terminates the registration.
On the other hand, a user can modify the username used for the registration process by operating keys of a self terminal. Thus, many users may repeatedly use the same username.
When the users repeatedly use the same username, the proxy server may repeatedly register the same value during the registration process. In this case, the proxy server updates the username with a currently registered value, causing a problem that a user who already uses the same username by registration cannot use a self username.
In another words, when using a prior standard SIP, the registration process is performed with user information inputted by users. As a result, if the users directly input or modify various sorts of information and set a repeated value by mistake, users who registered the username in advance may not use self username, thereby deteriorating system efficiency and making management difficult.